Tire tread splitting apparatus



G. F. CONNELLY Re. 20Q711 TIRE TREAD SPLI'ITING APPARATUS 7 OriginalFiled April 12, 1935 5 Sheets-Sheet 1 INVENTOR. 2 L 7 .Z .GEORGE FCNELLYMay 3, 1938. G. F, CQNNELLY Re. 20,711

TIRE TREAD SPLITTING APPARATUS Original Filed April 12, 1955 5Sheets-Sheet 2 llll JNVENTOR. GEORGE F Co/wvtLLr y 3, G. F. CONNELLY Re.20,711

TIRE TREAD SPLITTING APPARATUS Original Filed April 12, 1953 5Sheets-Sheet 3 V I INVENi'OR.

GEORGE F COIVIVELLY Reissued May 3, 1938 UNITED STATES PATENT OFFICETIRE TREAD SPLITTING APPARATUS Original No. 1,945,883,

Serial N0. 665,775, April 12, 1933.

dated February 6, 1934, Application for reissue April 29, 1936, SerialNo. 77,072

14 Claims.

This invention relates particularly to an apparatus for splitting orsevering the Worn tread surface from a pneumatic tire while maintainingthe said tire in its circular form.

An object of the invention is to provide an apparatus adaptedparticularly to split or remove the worn rubber tread of a pneumatictire from the carcass of the tire, preliminarily to retreading thecarcass.

A further object of the invention is to provide an apparatus forremoving the tread surface of a pneumatic tire which will, by continuousoperation, automatically cut any selected thickness of the worn treadsurface from the tire, means being provided in the apparatus to maintainthe normal tread surface of the tire in a flattened position during theperiod of time in which the said tread surface is being split from thecarcass.

Other objects and advantages are to provide an apparatus for removingthe treads from tires that will be superior in point of simplicity,inexpensiveness of construction, po-sitiveness of operation, andfacility and convenience in use and general efllciency.

In this specification and the annexed drawings, the invention isillustrated in the form considered to be the best, but it is to beunderstood that the invention is not limited to such 30 form, because itmay be embodied in other forms; and it is also to be understood that inand by the claims following the description, it is desired to cover theinvention in whatsoever form it may be embodied.

In the accompanying drawings:

Fig. 1 represents a front elevation of a tire tread splitting apparatusconstructed in accordance with my invention, a portion thereof beingbroken away to show the interior construction 40 thereof.

Fig. 2 is a side elevation of Fig. 1, a portion of this view being insection to show the interior construction, said view being takensubstantially on the line 2-2 of Fig. 1.

Fig. 3 is a vertical section taken through Fig. 1 on the line 3-3.

Fig. 4 is a fragmentary view taken on the line 44 of Fig. 1.

Fig. 5 is an enlarged plan view of the guide for supporting the cuttingknife.

Fig. 6 is a cross section taken through Fig. 5 on the line 65.

Fig. '7 is a longitudinal section taken through Fig. 5 on the line I'I.

Fig. 8 is an enlarged cross section taken (Cl. l64-35) through thepressure rollers and the cutting knife, and showing the method ofsplitting the tread surface from the tire.

Fig. 9 is an enlarged cross section taken through one of the guides forsupporting the 5 tire during the splitting operation.

Fig. 10 is a fragmentary view showing a modified form of apparatus forraising and lowering the lower feed roller.

In the art of stripping or removing tread sur- 10 faces from pneumatictires, to put said tires in condition to be retreaded, it is customarypractice to either cut the worn tread surface from the tire by hand, orto scrape the same oif, or remove it by abrasive wheels, all of whichmethods depend entirely on the hand work and skill of the operator toeffect removal of the tread surface, and as a result there is not auniformity of product. My apparatus is designed to elimimate the handwork usually involved in removing the tread surface from the tire, andto perform the entire operation mechanically, with the result that thefinished product is uniform, and the cost of removing the tread surface,as well as the period of time necessary to effect removal of said treadsurface, is materially reduced below both the cost and time accruingwhere the tread removal is effected by hand.

In detail the construction illustrated in the drawings comprises a frameof the tire splitting machine which is generally designated by thenumeral I, and which includes the foundation structure on which all ofthe operating parts of the machine are mounted. A pair of pulleys 2 and3 are arranged in spaced relation upon the upper side of the frame I,each of said pulleys being supported on shafts, the axes of which arehorizontally disposed. The pulley shaft 4 is rotatably supported in afixed bearing 5, while the pulley shaft 3' is rotatably supported in abear- 4O ing 6 which is slidably guided on a trackway I on the upperpart of the frame I. The shaft bearing 5 is adjustable on the framethrough the instrumentality of the threaded shaft 8 having a a handwheel thereon, whereby the position of the pulley 3 relative to thepulley 2 may be regulated as .desired. A pulley 9 is mounted on theother end of the shaft 4, said pulley 9 being drivingly connected by abelt I!) to a pulley I l on the shaft of a driving motor I2.

A band knife I I is mounted around the peripheries of the pulleys 2 and3, and the lower run of said knife, between the pulleys 2 and 3, isconfined within a guideway I5 formed in a guide member I6, mountedadjacent the upper 55 side of the frame I. The housing I6 is formed inseparable halves Mia. and I6b, which halves are bolted together adjacenttheir opposite ends. The side of the housing I6 which faces the tire tobe cut or split, is tapered or beveled as shown at I60. A pair of likemembers |6d are recessed into the beveled side of the housing to guideand support the band knife at the cutting edge. The inserts Hid are cuton a taper which corresponds approximately to the cutting edge of theband knife, and the inserts may be sharpened or replaced in a relativelysimple manner.

The interior of each of the separable halves Mia and Ifib are hollowedout as at I6g to receive spaced rollers Mia and "if. Each of the rollersis rotatably mounted in a frame IBh slidably confined in the recess I6y.A threaded shaft I67 is mounted in the housing I 6 to engage the frameII-lh, for the purpose of advancing or withdrawing the rollers Mia andIGf toward or away from the rear edge of the band knife I4. As thecutting edge of the band knife may-become worn through continuouscutting operations, the rollers..|6e.and 16f permit the said knife to beadvanced and kept at the'proper point for efficient cutting operation.The housing i6 supports the lowerrun of the band knife on a truehorizontal plane at the. point where the knife iscutting the worn tread.surface from a tire, as will be hereinafter described.

The vertically disposed-portion of the frame I is provided with aguideway thereon, on which aslide I8 is confined. A gear rack I 9 isarranged in vertical relation on the guide H. A shaft '20 journaled in abearing 2| on the slide I8 has a pinionz22 on anend thereof which mesheswith the gear rack I 9. The shaft.2ll has a worm wheel 23 rotatablymounted thereon in meshing engagement with a worm 24 journaled on theslide 18, said worm 24 having a hand wheel 25 thereon for rotatingtheworm wheel-23 and the pinion 22 which meshes with the gear rack I9for raising or lowering the slide IBv on the-guideway IT. The shaftt20.is also provided with a hand wheel 26 slidablysplined thereon.

The hand wheel 26 is slidable axially on the shaft 2| to engage ordisengage With the worm Wheel23. Whenthe hand wheel 26 is-declutchedfrom the worm wheel 23, it is'possible to raise or lower the slide I8relative to the gear rack much faster than by raising or lowering thesame through the worm and worm wheel. When the .hand wheel 26 isclutched with the worm wheel,

then it becomespossible by rotating the hand Wheel25 and the-worm 24,-to obtain a micrometric movement of the slide I B. When the hand wheel26 is in clutching engagement with theworm wheel 23, the worm 24 thereonacts as a brake or look to stop indiscriminate rotation of the shaft 20and thus holds the slide I8 at any set position.

The slide:|8 is connected by a cable 21 to a counterweight 28, whichcounterweight counterbalances the weight of the slide I8 and theoperating mechanism which is mounted thereon, as will be hereinafterexplained.

A driving screw or worm 29 is supported in vertical position in bearings30 on the frame I, said driving-screw 29 having a bevel pinion 3| on itsupper end in meshing engagement with a-bevel pinion 32 on the pulleyshaft 4. The drive screw 29 is thus coupled directly to the pulley shaftand is rotated in unison therewith. The screw or worm 33. at the. upperend of the shaft 29 has a left hand pitch, while the screw or worm 34 atthe lower end of said shaft has a right hand pitch.

A shaft 35 is journaled in bearings adjacent the upper side of the frameI, said shaft 35 having a corrugated feed roller 36 securely mountedthereon. The shaft 35 has a worm 31 on an end thereof which meshes withthe threaded portion 33 on the shaft 29, to drive said shaft in aclockwise direction. The feed roller 36 is arranged in front of andabove the upper half of. the housing I6 within which the band knife I4is confined. The shaft 35 lies on a horizontal plane and par- Iallelsthe plane of the lower run of the band knife I4. A line drawn on thevertical through the axis of the feed roller 36 approximately intersectsthe cutting edge of the band knife I4.

The slide I8. is provided with an extension arm '40 having a verticallydisposed bracket 4| on the outer end of said arm. A feed roller 42 isjournaled at its opposite ends in the upper end of the bracket 4|, thehorizontal axis of rotation of the feed roller 42 lying in the samevertical plane as the horizontal axis of the upper feed rollerSfi. Thecenter portion of the feed roller 42 is reduced in diameter to receive asprocket 43 therein. A sprocket chain 44 meshes with the sprocket 43 andwith a sprocket 45 fixed on the end of a shaft46, said shaft 46 beingjournaled at itshopposite ends in bearings 41 and 48 formed respectivelyon the bracket 4| and the bearing 2 I. The shaft 46 is provided with aworm 49 on the other end thereof, which Worm meshes with the threadedportion-34 on the drive shaft 29. The worm 49 thus drives the shaft 46and the lower feed roller 42 in a counterclockwise direction.

- The apparatus operates as follows: A pneumatic tire from which theworn treadsurface is to be split or severed, is placed in a verticalhanging position, having the lower feed roller 42 inserted within theinterior of the tire, whereby the said tire is supported onsaid'feedroller. The slide I3 is then raised by means of the gear rack heretoforedescribed, until the upper or tread surface of the tire-is brought into.contact with the underside of the upper feed roller :36. -As the-lowerfeed roller raises the treadportion of the tire into contact with theupper feed roller,

the tread surface of the tire is gradually flattened outuntilpractically the entire tread surface thereof lies on a horizontal plane.When the tread surface of the tire is thus squeezed between the rollers,it lies immediately in front ofthe cutting edge of the band knife. Thethickness of the tread surface to besplit from the tire, or the depth ofthe cut to be made by the band'knife, is regulated by the extent of thecompressing force applied to the tire in squeezing the tire between theupper and lowerfeed rolls.

. The upper feed roller 36 is formed with a corrugated periphery, thecentersection thereof being made of metal and theopposite end. sectionsof rubber. The lower feed roller 42 forces the tread surface of the tireagainst the bottom surface of the upper feed roller 36 and the act ofcompressing the tread section between said rollers Will, in some cases,cause the non-metal section on the roller 36 to yield to accommodate thetread surface of the tire, thus enabling the band knife to cut theextreme edges of the tread surface from the tire.

The upper feed roller 36 and the lower feed roller 42' cause the tirecarcass to be rotated or fed toward the cutting edge of the band knife.During the splitting operation the band knife I4 moves continuously, asdoes the tire carcass 5D, and'by gradually adjusting the extent ofcontact of the band knife with the tire carcass, it is possible torernove as much of the tread surface of the tire carcass in a singleoperation, as may be desired, and with the assured result that the saidtire carcass will have had a uniform amount of tread surface removedtherefrom around the entire circumference thereof.

The tire 50 is supported in a vertical position during the cuttingoperation by means of substantially spherical guide rollers 51 and 52,which are inserted within the interior of the tire "on diametricallyopposite sides thereof. The rollers 5| and 52. are rotatably mounted onthe ends of gear racks 53 and 54 respectively, said gear racks beingconfined to movement in a. horizontal direction in the slide arm 40. Ashaft 55 is journaled in the arm 40 and has a sprocket 55 thereonmeshing with the rack arms 53 and 54, whereby the rollers 5i and 52 maybe advanced into and from position within the interior of the tirecarcass. The rollers 5i and 52 when extended into the tire, prevent anylateral deflection of the tire during the splitting operation. Upon thecompletion of the splitting operation and after a sufiicient amount oftread surface has been removed from the tire, the slide l8 would belowered on the guideway IT, to drop the feed rollers apart, after whichthe guide rollers 5| and 52 would be withdrawn from the interior of thetire carcass, and the tire would be removed in readiness to have a newtread surface vulcanized thereon. With my apparatus, the tread surfaceof the tire is removed therefrom without deforming or mutilating thenatural shape of the tire. To enable the tire to be retreaded, it isnecessary from a mechanical standpoint, that the tire be not do formedor otherwise misshapen, and by using my splitting apparatus it ispossible to cut the worn tread from the tire carcass, and at the sametime to not destroy the original shape of the tire.

It is desirable in the preparation of a tire to be retreaded that theold tread surface be removed and that the surfaces of the side Walls ofthe tire retain their original covering of rubber which is ordinarilynot subject to abrasive wear. It is also desirable and necessary toobtain the best and most uniform results in applying the new treadsurface that the edge of the cut away portion of the old tread betapered or gradually reduced in thickness so that the tire presents asubstantially smooth surface for the application of rubber that is to bevulcanized thereon to form the new tread surface. This manner ofremoving the old tread is accomplished in an efficient and simple mannorwith my invention as may be seen from Fig. 1 of the drawings. Asillustrated in Figv 1 that portion of the knife which is performing thecut is perfectly straight and passes through the tread of the tire on astraight line. However, due to the fact that the portion of the tirebeing cut by the knife is constrained by the rollers 35 and 42 to lieflat and the adjacent side walls curve away from the rollers, theportion cut away is actually curved and gradually tapered at its edges.A typical section of the cut away portion and the shape of the tire fromwhich it has been cut is illustrated in the view of the tire in sectiondirectly beneath the point where the knife is shown in Fig, 1. Thus,while I employ a perfectly straight knife for cutting the tire, theresult of the cut is a curved surface which merges gradually rather thanabruptly into the uncut surface of the side Walls.

Although I have shown and described an endless band knife for use incutting the worn tread from the the carcass, it is to be understood thata reciprocating knife might be substituted in lieu thereof. Likewise,the upper feed roller 36 may be part rubber and part metal as described,altho it would be clearly within the purview of the invention to form itthroughout the entire length of metal. I have found also that on smallsized tires, the lower feed roller 42 need not be driven.

In the modified form of structure shown in Fig. 10, I have indicated aportion of a frame I having a slide !8' guided thereon, saidslideCarrying a lower feed roller 42 on its upper end. The slide I8 isprovided with a piston rod 60 thereon reciprocatingly confined. in anair cylinder SI for raising and lowering the said slide member andmoving the lower feed roller 36. The method of raising and lowering theslide i8 by means of air pressure, has the advantage over the system ofraising said slide by means of a gear and rack, in that it may beoperated much faster and eliminates any manual effort in placing thetire under compression.

Having thus described this invention, what I claim and desire to secureby Letters Patent is:

1. An apparatus to cut the curved tread from a full circle tireconsisting of a driven roller to be inserted within the tire and tosup-port the tire in hanging position thereon; a driven roller to con.-tact the outer tread surface of the tire, the axes of said drivenrollers being parallel on the horizontal plane and in alignment on thevertical plane; means to move the roller on which the tire is supportedinto contact with the other roller to thereby flatten the tread portionof the tire; a band knife having the cutting edge thereof disposed. on ahorizontal plane between the rollers; means to advance said knife intoengagement with the tread surface of the tire confined between therollers; and means to drive the band knife and rollers in unison.

2. An apparatus to cut the curved tread from a full circle tire,including a frame having a vertical guide thereon; a slide on saidguide; a rack and gear on the guide and slide for raising and loweringthe slide on the guide; a bracket on the slide; a horizontally disposedroller on said guide to extend within a tire and to support the tire inhanging position thereon; a shaft journaled on said bracket and guidedrivingly connected to said tire supporting roller; and a driven shafton the frame in driving engagement with said last mentioned shaft.

3. An apparatus to cut the curved tread from a full circle tire,including a frame having a ver tical guide thereon; a slide on saidguide; a rack and gear on the guide and slide for raising and loweringthe slide on the guide; a bracket on the slide; a horizontally disposedroller on said guide to extend within a tire and to support the tire inhanging position thereon; a shaft journaled on said bracket and guidedrivingly connected to said tire supporting roller; a shaft journaled onthe frame drivingly connected to said second mentioned roller and to thedriven shaft on the frame; and band knife having the cutting edgethereof disposed on a horizontal plane adjacent said second mentionedroller to split the tread surface from a tire when said tread isflattened between said rollers.

4. An apparatus to cut the curved tread from a full circle tire,including a frame having a vertical guide thereon; a slide on saidguide; a rack and gear on the guide and slide for raising and loweringthe slide on the guide; a bracket on the slide; a horizontally disposedroller on said guide to extend within the tire and to support the tirein hanging position thereon; a sprocket arranged between the ends ofsaid roller; a shaft journaled'on' said bracket and guide; a chaindrivingly connecting said sprocket and shaft; a driven shaft on theframe in driving engagement with said last mentioned shaft; a rollerjournaled on the frame in parallel and vertical alignment with and abovethe first mentioned roller; a shaft journaled on the frame drivinglyconnected to said second mentioned roller and to the driven shaft on theframe; and a band knife having the cutting edge thereof disposed on ahorizontal plane adjacent said second mentioned roller to split thetread surface from a tire when said tread is flattened between saidrollers.

5. An apparatusto cut the curved tread from a full circle tire,including a frame having a vertical guide thereon; a slide on saidguide; a rack and gear on the guide and slide for raising and loweringthe slide on the guide; a bracket on the slide; a horizontally disposedroller on said guide to extend within a tire and to support the tire inhanging position thereon; a shaft journaled on said bracket and guidedrivingly connected to said tire supporting roller; a driven shaft onthe frame in driving engagement with said last mentioned shaft; a rollerjournaled on the frame in parallel and vertical alignment with and abovethe first mentioned roller; a shaft journaled on the frame drivinglyconnected to said second mentioned roller and to the driven shaft on theframe; a band knife having the cutting edge thereof disposed on ahorizontal plane adjacent said second mentioned roller to split thetread surface from a tire when said tread is flattened between saidrollers; and a pair of guide rollers arranged on the bracket to enterthe inte rior of the tire on diametrically opposite sides thereof and tosupport the same during the split ting operation.

6. An apparatus to cut the curved tread from a full circle tire,including a frame having a vertical guide thereon; a slide on saidguide; a rack and gear on the guide and slide for raising and loweringthe slide on the guide; a bracket on the slide; a horizontally disposedroller on said guide to extend within a tire and to support the tire inhanging position thereon; a sprocket arranged between the ends of saidroller; a shaft journalcd on said bracket and guide; a chain drivinglyconnecting said sprocket and shaft; a driven shaft on the frame indriving engagement with said last mentioned shaft; a roller journaled onthe frame in parallel and vertical alignmentwith and above the firstmentioned roller; a shaft journaled on the frame drivingly connectedtosaid second mentioned roller and to the driven shaft on the frame; aband knife having the cutting edge thereof disposed on a horizontalplane adjacent said second mentioned roller to split the tread surfacefrom a tire when said tread is flattened between said rollers; and apair of guide rollers arranged on the bracket to enter the interior ofthe tire on diametrically opposite sides thereof and to support the sameduring the splitting operation.

7. An apparatus to cut the curved tread from a full circle tire,including a frame having a vertical guide therein, a slide on saidguide; a pair of matching driven feed rollers on the frame and slide;means to move the slide with the driven feed roller thereon toward orfrom the roller on the frame; a band knife having the cutting edgethereof disposed on a plane parallel to. the axes of rotation of saidrollers and arranged between bracket on the slide; roller on said guideto extend within a tire and 'said rollers; a pair of guide rollersadjustably confined on the slide on diametrically opposite sides thereofto support the tire in a freely rotatable position; and means to drivethe feed rollers to advance the tire into contact with the band knife.

8. An apparatus to cut the curved'tread from a full circle tire,including a frame having a vertical guide therein, a slide on saidguide; a pair of matching driven feed rollers on the frame and slide;means to move the slide with the driven feed roller thereon toward orfrom the roller on the frame; a band knife having the cutting edgethereof disposed on a plane parallel to the axes of rotation of saidrollers and arranged between said rollers; a pair of guiderollers-adjustably confined'on the slide on diametrically opposite sidesthereof to support the tire in a freely rotatable position; toothedmechanism for moving the guide rollers into and from supporting ('20position in the tire; and means to drive the feed rollers to advance thetire into contact with the band knife.

9. An apparatus to cut the curved tread from a full circle tireconsisting of a roller to be inserted within the tire and to support thetire in hanging position thereon; a driven roller to contact the outertread surface of the tire, the axes of said rollers being parallel onthe horizontal plane and in alignment on the vertical plane; means tomove the roller on which the tire is supported towards the other rollerto thereby flatten the tread portion of the tire; a knife having thecutting edge thereof disposed on a horizontal plane between the rollers,and means to drive the knife and one of the rollers in unison.

10. An apparatus to cut the curved tread from a full circle tire,including a frame having a vertical guide thereon; a slide on saidguide; means for raising and lowering the slide on the guide; a a.horizontally disposed to support the tire in hanging position thereon; adriven shaft on the frame; a roller journaledon the frame in paralleland vertical alignment with and above the first mentioned roller; ashaft journaled on the frame drivingly connected to said secondmentioned roller and to the driven shaft on the frame; and a knifehaving the cutting edge thereof disposed on a horizontal'plane adjacentsaid second mentioned roller to split the tread surface from atire whensaid-tread is flattened between said rollers.

11. An apparatus to cut the curved tread from a full circle tire,including a frame having a vertical guide thereon; a slide on saidguide; means for raising and lowering the slide on the guide; a bracketon the slide; a horizontally disposed roller on said guide to extendwithin a tire and to support the tire in hanging positionthereon; adriven shaft on the frame; a roller journaled on the frame in paralleland vertical alignment with and above the first mentioned roller; ashaft journaled on the frame drivingly connected to said secondmentioned roller and to the driven shafton the frame; a knife having thecutting edge thereof disposed on a horizontal plane adjacent said secondmentioned roller to split the tread surface from a tire when said treadis flattened between said rollers; and a pair of guide rollers arrangedon the bracket to enter the interior of the tire on diametricallyopposite sides thereof and to support the same during the splittingoperation.

full circle tire comprising a roller supported in a position to bedisposed within the tire, a second roller arranged to contact the outertread surface of the tire, said rollers being parallel and the axesthereof being in vertical alignment, means for moving one of saidrollers relative to the other to flatten the portion of the tiredisposed between them, a knife for forming a fiat out between therollers and parallel to their axes, the surface cut by the knifebecoming curved and merging gradually into the uncut surface of the tireas the same assumes its normal shape upon removal of the tire frombetween the rollers and means for driving one of said rollers and saidknife in unison.

13. An apparatus for cutting the tread from a full circle tirecomprising a roller supported in a position to be disposed within thetire; a second roller arranged to contact the outer surface of the tire,said rollers being parallel and the axes thereof being in verticalalignment, means for moving one of said rollers relative to the other toflatten that portion of the tire disposed between them, a knife having astraight cutting edge disposed between the rollers and parallel to theiraxes; and means for simultaneously driving the rollers to advance thetire and for moving the knife to form a straight out at the portion ofthe tire between the rollers, said tire assuming its normal shape uponremoval of the tire from between the rollers, the cut portion therebyassuming the normal curved contour with gradually tapered marginaledges.

14. An apparatus for cutting the tread from a full circle tirecomprising a roller arranged to be positioned within the tire; a secondroller parallel to the first and engageable with the outer surface ofthe tire; means to effect relative movement of the rollers toward eachother to compress that portion of the tire immediately between them to asubstantially flat position; means for driving one of the rollers toadvance the tire between them; and a knife having a straight cuttingedge engaging and severing the tire tread as it passes between therollers in a plane parallel to the axes of the rollers and means fordriving one of said rollers-and said knife in unison GEORGE F. CONNELLY.

